1. Field of the Invention
The present invention relates to a rearview mirror assembly for a motor vehicle, and more particularly to an attachment structure for a mirror support of an automotive rearview mirror assembly.
2. Description of the Relevant Art
Rearview mirror assemblies for use on motor vehicles include a mirror holder supported by a mirror holder support unit which is attached to a bracket connected to a motor vehicle body. When the mirror held by the mirror holder is damaged, the rearview mirror is not replaced in its entirety since it would be time-consuming and costly to replace the entire rearview mirror assembly with a new rearview mirror assembly. Instead, the mirror holder is detached from the bracket, then the mirror holder is removed from the mirror holder support unit, and replaced with a mirror holder on which a new mirror is mounted. To allow such a mirror replacement, the mirror holder support unit is detachably mounted on the bracket.
Japanese Laid-Open Utility Model Publication No. 62(1987)-170346 discloses a rearview mirror assembly for a motor vehicle, which includes a mirror holder support member and a metal plate disposed behind the mirror holder support member. The metal plate and the mirror holder support member are fastened to each other by a plurality of screws. The metal plate has fingers on its upper end which engage a bracket, with the lower end of the metal plate being fixed to the bracket by screws from below. The mirror holder support member is thus attached to the bracket. With such an attachment structure, however, since the lower end of the metal plate is attached to the bracket by the screws from below, the lower end tends to wobble in the horizontal direction.
A rearview mirror assembly disclosed in Japanese Utility Model Publication No. 63(1988)-37321 has a mirror holder support member having engagement holes defined in its upper end and screw threading portions in its lower end. The engagement holes receive fingers on a bracket, and the screw threading portions and a lower end of the bracket are fastened to each other by screws, thereby attaching the mirror holder support member to the bracket. The upper and lower ends of the mirror holder support member are fixed to the bracket by the fingers and screws, respectively. Consequently, the bracket cannot absorb the thermal expansion of the mirror holder support member due to the heat thereof.